System for testing optical transmitters

ABSTRACT

A system for testing optical transmitters including a testing unit, a sensor board, one or more support rails, and a driver is provided. The testing board includes sockets that each receive a substrate supporting a plurality of optical transmitters, and the sensor board includes optical receivers. The one or more support rails are attached to one of the testing board or the sensor board and are designed to engage the other of the testing board or the sensor board. The one or more support rails are configured to substantially align each of the optical receivers with a corresponding socket. The driver is in electrical communication with the optical transmitters and the one or more optical receivers such that the driver can apply a current input to at least, one of the optical transmitters and monitor a corresponding output parameter.

FIELD OF THE INVENTION

The present disclosure relates generally to optoelectronic devices and,more particularly, to apparatuses, methods, and associated computerprogram products for predicting failure of optical transmitters such asvertical-cavity surface-emitting lasers (VCSELs).

BACKGROUND OF THE INVENTION

Optoelectronic communication systems, often utilized in data centers,include cables that transmit signals over optical media. Theseoptoelectronic communication systems may utilize active optical cables(AOC) as optical media and may also include separate circuitry thatfacilitates the transmission of optical signals along the optical cablesusing one or more transducers or optical transmitters. For example,modern optoelectronic communication systems may utilize vertical-cavitysurface-emitting lasers (VCSELs) as optical transmitters that convertelectrical signals to optical signals for transmission by an opticalcable. One of the primary modes of failure in optical communicationsystems is the random failure of the optical transmitters.

Applicant has identified a number of additional deficiencies andproblems associated with conventional VCSELs and associated testingmethods. Through applied effort, ingenuity, and innovation, many ofthese identified problems have been solved by developing solutions thatare included in embodiments of the present invention, many examples ofwhich are described in detail herein.

BRIEF SUMMARY OF THE INVENTION

A system for testing optical transmitters including a testing unit isprovided. The testing unit may include a testing board supporting one ormore sockets via a top surface of the testing board, and each socket mayreceive a substrate supporting a plurality of optical transmitters. Eachoptical transmitter may also convert electrical signals to correspondingoptical signals for transmission by the optical transmitter. The testingunit may also include a sensor board supporting one or more opticalreceivers via a bottom surface of the sensor board where each opticalreceiver may receive the optical signals transmitted by the plurality ofoptical transmitters and convert the optical signals to correspondingelectrical signals. The testing unit may further include one or moresupport rails attached to one of the testing board or the sensor boardand configured to engage the other of the testing board or the sensorboard. The one or more support rails may substantially align each of theone or more optical receivers of the sensor board with a correspondingsocket of the testing board such that the plurality of opticaltransmitters is in optical communication with the one or more opticalreceivers in an operational mode of the testing unit. The system fortesting optical transmitters may also include a driver in electricalcommunication with the plurality of optical transmitters of the one ormore sockets and in electrical communication with the one or moreoptical receivers of the sensor board. The driver may apply a currentinput to at least one of the plurality of optical transmitters and maymonitor a corresponding output parameter.

In some embodiments, the driver is further may determine a pass state ora fail state of the plurality of optical transmitters based on acomparison of the output parameter to an output parameter threshold.

In some cases, the system for testing optical transmitters may alsoinclude a backplane element supporting one or more testing units, andthe backplane element may be in electrical communication with the one ormore testing units. In such an embodiments, the backplane element maysupport four testing units.

In a further case, the driver is electrically connected to the backplaneelement via a rigid-flex printed circuit board. In such an embodiment,the system for testing optical transmitters may further include fourdrivers that may provide a current to one of the testing units supportedby the backplane element.

In other embodiments, the system for testing optical transmitters mayfurther include a control unit in electrical communication with thedriver and that may execute a testing method with respect to theplurality of optical transmitters of the testing unit.

In some cases, each testing board may support eight sockets. Each socketmay receive a substrate supporting sixteen optical transmitters.

In other embodiments, the plurality of optical transmitters includevertical-cavity surface-emitting lasers, and the one or more opticalreceivers include photodiodes.

In some embodiments, the distance between the socket and the sensorboard is less than 9.33 mm.

In some still further embodiments, the sensor board includes a maleconnector configured to be received by a corresponding female connectordefined by the testing board.

In other cases, the testing unit defines a connecting portion having afirst width and an edge connector and defines a testing portion having asecond width, where the second width is larger than the first width. Insuch a case, the edge connector may be configured to be received by acorresponding connector of a backplane element. Still further, thedriver may also be in electrical communication with the backplaneelement via a rigid-flex printed circuit board, and the backplaneelement may be in electrical communication with the testing unit via theedge connector such that the current input applied by the driver isreceived by the plurality of optical transmitters via the backplaneelement.

A method of manufacturing a system for testing optical transmitters isprovided. The method may include providing a testing unit. The testingunit may include a testing board supporting one or more sockets via atop surface of the testing board, and each socket may receive asubstrate supporting a plurality of optical transmitters. Each opticaltransmitter may also convert electrical signals to corresponding opticalsignals for transmission by the optical transmitter. The testing unitmay also include a sensor board supporting one or more optical receiversvia a bottom surface of the sensor board where each optical receiver mayreceive the optical signals transmitted by the plurality of opticaltransmitters and convert the optical signals to corresponding electricalsignals. The testing unit may further include one or more support railsattached to one of the testing board or the sensor board and configuredto engage the other of the testing board or the sensor board. The one ormore support rails may substantially align each of the one or moreoptical receivers of the sensor board with a corresponding socket of thetesting board such that the plurality of optical transmitters is inoptical communication with the one or more optical receivers in anoperational mode of the testing unit. The method may also includeproviding a driver. The driver may be electrical communication with theplurality of optical transmitters of the one or more sockets and inelectrical communication with the one or more optical receivers of thesensor board. The driver may apply a current input to at least one ofthe plurality of optical transmitters and may monitor a correspondingoutput parameter.

In some embodiments, the method may also include providing a backplaneelement supporting one or more testing units.

In other embodiments, the method may also include providing one or moredrivers, where each driver provides a current to one of the testingunits supported by the backplane element.

In some other embodiments, the method may also include providing acontrol unit in electrical communication with the driver and may executea testing method with respect to the plurality of optical transmittersof the testing unit.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 shows a diagram of a system for testing optical transmitters inaccordance with some embodiments discussed herein;

FIG. 2 shows a block diagram of an example apparatus that may bespecifically configured in accordance with some embodiments discussedherein

FIG. 3 shows a side view of a testing unit in accordance with someembodiments discussed herein;

FIG. 4 shows a top view of a testing board of FIG. 2 in accordance withsome embodiments discussed herein;

FIG. 5 shows a perspective view of a socket, substrate, and plurality ofoptical transmitters in accordance with some embodiments discussedherein;

FIG. 6 shows a top view of a substrate of FIG. 4 in accordance with someembodiments discussed herein;

FIG. 6A shows a top view of a particular configuration of the substrateof FIG. 4 in accordance with some embodiments discussed herein;

FIG. 7 shows a bottom view of a sensor board of FIG. 2 in accordancewith some embodiments discussed herein;

FIG. 8 shows a flow chart illustrating an optical transmitter testingmethod in accordance with some embodiments discussed herein;

FIG. 9 shows a flow chart illustrating a continuity testing method of anoptical transmitter in accordance with some embodiments discussedherein;

FIG. 10 shows a flow chart illustrating an LIV testing method of anoptical transmitter in accordance with some embodiments discussedherein;

FIG. 11 shows a flow chart illustrating an IV testing method of anoptical transmitter in accordance with some embodiments discussedherein; and

FIG. 12 shows a flow chart illustrating a stress testing method of anoptical transmitter in accordance with some embodiments discussedherein.

DETAILED DESCRIPTION Overview

The present invention now will be described more fully hereinafter withreference to the accompanying drawings in which some but not allembodiments of the inventions are shown. Indeed, these inventions may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout. As usedherein, terms such as “front,” “rear,” “bottom,” “top,” etc. are usedfor explanatory purposes in the examples provided below to describe therelative position of certain components or portions of components. Asused herein, the term “module” encompasses hardware, software, and/orfirmware configured to perform one or more particular functions,including but not limited to conversion between electrical and opticalsignals and transmission of the same. As would be evident to one ofordinary skill in the art in light of the present disclosure, terms suchas “about” and “substantially” indicate that the referenced element orassociated description is accurate to within applicable engineeringtolerances. Additionally, as discussed herein, an example embodiment isdescribed with reference to a vertical-cavity surface-emitting laser(VCSEL) and photodiode as the optical transmitter and optical receiver,respectively; however, embodiments of the present invention may beequally applicable for use with any transceiver system and/or element.

Optical cables are comprised of optical fibers that may be utilized inconjunction with optical transmitters and receivers built intotransceiver modules and systems located at the ends of the opticalcables for transmitting and receiving optical signals. The transceivermodules may include Small Form-Factor Pluggable (SFP), Dual SFP, QuadSmall Form-factor Pluggable (QSFP), C-Form-Factor Pluggable (CFP), orany transceiver known or used in optical communication. The transceivermodules or systems may plug into suitable electrical communicationports, such as Gigabit Ethernet or InfiniBand® ports, of switching andcomputing equipment. Optoelectronic components in the transceivermodules and systems may convert the high-speed electrical signals outputby the ports into optical signals for transmission over optical fibers(e.g., via a VCSEL). In addition, the optoelectronic components onopposing ends of the optical fibers may receive the optical signals andconvert the optical signals into high-speed electrical signals for inputto the electrical communication ports and modules (e.g., via aphotodiode).

In many transceiver modules and systems, optical transmitters, such asVCSELs, are used to generate optical signals for transmission overoptical fibers. VCSELs in particular are favored for their highbandwidth and efficiency. In some implementations, an array of suchVCSELs is used to drive a corresponding array of optical fibers, whichare joined together in a ribbon configuration. Optical fibers may beconnected to both VCSELs and photodiode configurations on opposing endssuch that one or more photodiodes may receive the optical signals fromthe VCSELs at a receiving end of the fibers and convert the opticalsignals into electrical signals.

In manufacturing transceiver modules and systems, optical transmitters,such as VCSELs, are often subjected to various testing procedures inorder to determine the anticipated reliability of the components foundin the transceiver modules and systems. These testing procedures may beconducted prior to installation of the component in an operationalsystem. Conventional tests may only subject a limited number of VCSELsto an elevated temperature or current input for a period of time to,based upon the observed results, determine the expected reliability ofthe VCSEL once it is installed in an optical communication system.Conventional testing procedures, however, may fail to accuratelyidentify VCSELs that have a high likelihood of failure or are prone tocertain modes of failure (e.g., random failures). For example,conventional testing procedures often use broad tolerances, such thatVCSELs exhibiting characteristics associated with the random failure ofthe VCSEL are deemed to pass the testing procedure and are provided tousers for installation, putting the systems at risk of premature failurein operation.

Traditionally, failure in these transmitters (e.g., the VCSELs) requiresan entire optoelectronic transducer or associated optical assembly to bedeconstructed or replaced. Given the abundant use of opticaltransmitters in a single datacenter rack, such a deconstruction orreplacement process incurs substantial cost in terms of down time,labor, and other costs to the user. Furthermore, conventional testingapparatuses, methods, and computer program products used to predict thefailure of optoelectronic devices only allow for testing to be performedon a small number of devices during a single testing method. Theselimitations result in wide variability between tested components andincreased time-to-market for the resultant optical transmitters andassociated transceiver systems.

Additionally, these conventional testing methods, such those used withTO-can laser diode mounts (“TO-can”), may only test a limited number ofoptical transmitters in any single testing procedure. The limited samplesize for each testing procedure can result in increased variabilityamong VCSELs tested in different iterations of a particular testingmethod. Additionally, in conventional testing procedures with TO-cans,testing parameters such as ambient temperature that are relevant to theresultant reliability of the tested VCSELs may vary widely between eachTO-can. Said another way, conventional systems may fail to provideconsistent testing parameters across a large number of VCSELs.

Embodiments of the present invention that are described herein providean improved system and method for testing the reliability and accuratelypredicting the failure of a VCSEL prior to installation of the VCSEL inan operational optical communication system. For the sake of clarity andconvenience of description, the embodiments that are described belowrefer to a particular configuration, using VCSELs as opticaltransmitters. The principles of the present invention, however, maysimilarly be implemented using other types of emitters (e.g., othertypes of lasers), modulators, and switching elements, as well as otheroptoelectronic transceiver components (e.g., photodiodes and differentlyconfigured optical cables and connector modules).

System Hardware

With reference to FIG. 1, a system for testing optical transmitters 100is illustrated including a testing unit 102, a backplane element 104, adriver 108, a control unit 112, and a power supply 114. As describedhereinafter with reference to FIGS. 2-6A, the testing unit 102 mayinclude or otherwise support various optoelectronic components, such asoptical transmitters and optical receivers, so that one or more testingprocedures may be performed on the optoelectronic components supportedthereon. As shown, in some embodiments, the testing unit 102 may besupported by a backplane element 104 such that the backplane element 104is in electrical communication with the testing unit 102. To establishand maintain electrical communication, in some embodiments, the testingunit may include an edge connector 106 configured to be received by acorresponding connector of the backplane element 104. The connectionbetween the backplane element 104 and the testing unit 102 may be suchthat electrical signals may flow therebetween. Additionally, and asshown in FIG. 1, the backplane element 104 may also be configured tosupport one or more testing units 102 where each testing unit may definea corresponding edge connector 106 in order to electrically connect withthe backplane element 104. While reference hereinafter may be made toone testing unit 102 and/or one corresponding backplane element 104, thepresent disclosure contemplates that any number of testing units 102 maybe supported by a backplane element 104 and/or that the system 100 mayinclude any number of additional backplane elements 104. Furthermore, insome embodiments, the system 100 may not include a backplane element 104such that the testing unit may be directly connected to a driver 108 ora control unit 112. Said another way, the present disclosurecontemplates that any number of structural support elements (e.g.,datacenter racks, cabinets, testing chambers, or the like) may functionto support the testing unit 102 and/or may facilitate electricalconnection between the testing unit 102 and an electrical or currentinput device (e.g., the driver 108).

With continued reference to FIG. 1, the system 100 may also include adriver 108 configured to generate inputs (e.g., a current input) thatmay be applied to optoelectronic components (e.g., VCSELs) supported bythe testing unit 102. For example, the driver 108 may be configured togenerate and apply a stress current or voltage to the testing unit 102supported by the backplane 104. As described herein, the driver 108 mayalso be in electrical communication with a plurality of opticaltransmitters (e.g., a plurality of optical transmitters 502 in FIG. 5)of one or more sockets (e.g., one or more sockets 302 in FIG. 3) and inelectrical communication with the one or more optical receivers (e.g.,one or more optical receivers 314 in FIG. 3) of the sensor board (e.g.,a sensor board 304 in FIG. 3). The driver 108 may also be configured toapply a current input to at least one optical transmitter and to monitora corresponding output parameter (e.g., output voltage, operatingtemperature, etc.). Further, the driver 108 may receive electricalsignals output by the testing unit 102 that may be directed to a controlunit 112 described hereinafter. Furthermore, the driver 108 may includecircuitry and/or optoelectronic elements (e.g., a multiplexer)configured to multiplex outputs signals received by the driver 108 fromthe testing unit 102 into a signal combined signal for transmission overa shared transmission medium (e.g., an optical fiber or the like) to acontrol unit 112 or other device in electrical communication with thedriver 108. In some embodiments, the driver 108 may be furtherconfigured to determine a pass state or a fail state of any number of aplurality of optical transmitters based on a comparison of variousoutput parameters to corresponding output parameter thresholds.

As shown in FIG. 1, in some embodiments, the driver 108 may be inelectrical communication with the backplane element 104 via a rigid-flexprinted circuit board (“PCB”). Additionally, in some embodiments, thesystem 100 may include one or more drivers 108 configured to provideinputs to one or more testing units 102. By way of example, in someembodiments, the number of drivers 102 used by the system 100 maycorrespond to the number of testing units 102 used by the system suchthat each driver 108 provides an input to a corresponding testing unit102. By way of a more particular example as shown in FIG. 1, in someembodiments, the system 100 may include four (4) drivers 108 each inelectrical communication with a backplane element 104 and acorresponding testing unit 102. While illustrated with the driver 108providing inputs to only one corresponding testing unit 102, the presentdisclosure contemplates that any number of drivers may provide inputs toany number of testing units 102. Said another way, one driver 108 mayprovide inputs to multiple testing units 102 and/or multiple drivers 108may provide inputs to a single corresponding testing unit 102.

In some embodiments, the system 100 may also include a control unit 112configured to execute or otherwise control the operation of the testingmethods and procedures applied to the optoelectronic componentssupported by the testing unit 102. In some embodiments, the control unit112 may be in electrical communication with the driver 108 such thatelectrical signals may be provided to the driver 108 (e.g., currentinputs) and electrical signals may be provided from the driver 108 tothe control unit 112 (e.g., output parameters, multiplex signals, or thelike). As would be understood by one or ordinary skill in the art inlight of the present disclosure, with reference in particular to thedescription of FIG. 3 below, the control unit 112 may operate as acomputer or computer program product. In particular, the control unit112 may be configured to execute one or more testing methods (e.g.,measurements, algorithms, protocols, or the like) by directing orotherwise controlling operation of the driver 108. Thus, the controlunit 112 may provide commands to the driver 108 to apply various inputs(e.g., currents) to the testing unit 102 and may receive output data(e.g., electrical signals) from the testing unit 102 via the driver 108.

Furthermore, the control unit 112 may be configured to monitor orcontrol various other variables or parameters of the system 100. Forexample, the control unit 112 may be in electrical communication withone or more sensors (e.g., thermometers, pressure sensors, humiditysensors, accelerometers, photo resistors, barometers, and the like) soas to monitor input, output, and/or ambient conditions of the system100. For example, the control unit 112 may monitor the ambienttemperature of the system 100 and/or the output temperature of one ormore optoelectronic components (e.g., when subjected to a current input)via electrical communication with one or more thermometers. Althoughdescribed herein with respect to the control unit 112 executing testingmethods or procedures via input commands to the driver 108, the presentdisclosure contemplates that the driver 108 may also include some or allof the circuitry or operation of the control unit 112. Said another way,the driver 108 may be integral to the control unit 112 in physicalstructure and/or operation. Similar to the backplane element 104 and thedriver 108 above, in some embodiments, the system 100 may comprise oneor more control units 112 configured to direct the operation of one ormore drivers 108. In any embodiment described herein, the system 100 mayinclude one or more power supplies 114 configured to provide power toone or more of the control unit 112 and/or the driver 108.

Regardless of the type of device that embodies the control unit 112 orthe driver 108, the control unit 112 and/or driver 108 may include or beassociated with an apparatus 200 as shown in FIG. 2. In this regard, theapparatus 200 may include or otherwise be in communication with aprocessor 202, a memory device 204, a communication interface 206,and/or a user interface 208. As such, in some embodiments, althoughdevices or elements are shown as being in communication with each other,hereinafter such devices or elements should be considered to be capableof being embodied within the same device or element and thus, devices orelements shown in communication should be understood to alternatively beportions of the same device or element.

In some embodiments, the processor 202 (and/or co-processors or anyother processing circuitry assisting or otherwise associated with theprocessor) may be in communication with the memory device 204 via a busfor passing information among components of the apparatus 200. Thememory device 204 may include, for example, one or more volatile and/ornon-volatile memories. In other words, for example, the memory device204 may be an electronic storage device (e.g., a computer readablestorage medium) comprising gates configured to store data (e.g., bits)that may be retrievable by a machine (e.g., a computing device like theprocessor). The memory device 204 may be configured to storeinformation, data, content, applications, instructions, or the like forenabling the apparatus 200 to carry out various functions in accordancewith an example embodiment of the present invention. In this regard, thememory device 204 may store various testing procedures, testingparameters, and/or threshold values configured to evaluate thereliability of a VCSEL as discussed below with reference to FIGS. 8-12.For example, the memory device 204 could be configured to buffer inputdata for processing by the processor 202. Additionally or alternatively,the memory device 204 could be configured to store instructions forexecution by the processor 202.

As noted above, the apparatus 200 may be embodied by the driver 108 orthe control unit 112 configured to be utilized in an example embodimentof the present invention. However, in some embodiments, the apparatus200 may be embodied as a chip or chip set. In other words, the apparatus200 may comprise one or more physical packages (e.g., chips) includingmaterials, components and/or wires on a structural assembly (e.g., abaseboard). The structural assembly may provide physical strength,conservation of size, and/or limitation of electrical interaction forcomponent circuitry included thereon.

The processor 202 may be embodied in a number of different ways. Forexample, the processor 202 may be embodied as one or more of varioushardware processing means such as a coprocessor, a microprocessor, acontroller, a digital signal processor (DSP), a processing element withor without an accompanying DSP, or various other processing circuitryincluding integrated circuits such as, for example, an ASIC (applicationspecific integrated circuit), an FPGA (field programmable gate array), amicrocontroller unit (MCU), a hardware accelerator, a special-purposecomputer chip, or the like.

In an example embodiment, the processor 202 may be configured to executeinstructions stored in the memory device 204 or otherwise accessible tothe processor 202. Alternatively or additionally, the processor 202 maybe configured to execute hard coded functionality. As such, whetherconfigured by hardware or software methods, or by a combination thereof,the processor 202 may represent an entity (e.g., physically embodied incircuitry) capable of performing operations according to an embodimentof the present invention while configured accordingly. Thus, forexample, when the processor 202 is embodied as an ASIC, FPGA or thelike, the processor 202 may be specifically configured hardware forconducting the operations described herein. Alternatively, as anotherexample, when the processor 202 is embodied as an executor of softwareinstructions, the instructions may specifically configure the processor202 to perform the algorithms and/or methods described herein when theinstructions are executed. However, in some cases, the processor 202 maybe a processor 202 of a specific device (e.g., a control unit 112 ordriver 108 as shown in FIG. 1) configured to be employed by anembodiment of the present invention by further configuration of theprocessor 202 by instructions for performing the algorithms and/oroperations described herein.

Meanwhile, the communication interface 206 may be any means such as adevice or circuitry embodied in either hardware or a combination ofhardware and software that is configured to receive and/or transmit databetween computing devices and/or servers. For example, the communicationinterface 206 may be configured to communicate wirelessly with the oneor more drivers 108 and/or testing units 102, such as via Wi-Fi,Bluetooth, or other wireless communications techniques. In someinstances, the communication interface may alternatively or also supportwired communication. For example, the communication interface 206 may beconfigured to communicate via wired communication with other componentsof the drive 108 and/or testing unit 102.

In some embodiments, the apparatus 200 may optionally include a userinterface 208 in communication with the processor 202, such as by theuser interface circuitry, to receive an indication of a user inputand/or to provide an audible, visual, mechanical, or other output to auser. As such, the user interface 208 may include, for example, akeyboard, a mouse, a display, a touch screen display, a microphone, aspeaker, and/or other input/output mechanisms. The user interface mayalso be in communication with the memory 204 and/or the communicationinterface 206, such as via a bus.

With reference to FIG. 3, a testing unit 102 of the system 100 isillustrated. As shown, the testing unit 102 may include a testing board300, a sensor board 304, one or more support rails 306, and an edgeconnector 106. As shown, in some embodiments, the testing board 300 maybe configured to support one or more sockets 302 via a top surface ofthe testing board 300. As described hereinafter with reference to FIGS.4-6A, the one or more sockets 302 may receive a substrate supporting oneor more optical transmitters for transmitting optical signals (e.g., asubstrate 500 and an optical transmitter 502 in FIG. 5). The testingboard 300 of the testing unit 102 may include a substrate, circuitboard, or any other support structure which allows electrical signals tobe directed to the socket 302, and subsequently to the opticaltransmitters supported thereon, from the driver 108 via the backplane104 (in FIG. 1). In particular, the testing board may define one or moreelectrical traces, connections, or the like configured to allowelectrical communication between the plurality of optical transmitters(e.g., optical transmitters 502 in FIG. 5) and the driver 108 (see FIG.1). As described above with reference to FIG. 1, the testing board 300(e.g., of the testing unit 102) may define an edge connector 106configured to be received by a corresponding connector of the backplaneelement 104. The connection between the backplane element 104 and thetesting unit 102 may be such that electrical signals may flowtherebetween.

The testing unit 102 may also include a sensor board 304 supporting oneor more optical receivers 314 (e.g., photodiodes) via a bottom surfaceof the sensor board 304. As described more fully hereinafter, the one ormore optical receivers may be configured to receive optical signalstransmitted by a plurality of optical transmitters and may be configuredto convert the optical signals to corresponding electrical signals. Asshown in FIG. 3, the one or more optical receivers 314 may be in opticalcommunication via alignment of the testing board 300 with the sensorboard 304. For example, the testing unit 102 may be configured such thatthe top surface of the testing board 300 supporting the one or moresockets 302 is disposed opposite the bottom surface of the sensor board300 supporting the one or more optical receivers 314. The testing unit102 may further include one or more support rails 306 attached to one ofthe testing board 300 or the sensor board 304, and the one or moresupport rails 306 may be configured to attach the testing board 300 tothe sensor board 304. While illustrated with three (3) support rails 306in FIG. 3, the present disclosure contemplates that any number ofsupport rails may be used in any configuration. Additionally, thesupport rails 306 may be attached to either one of the sensor board 304or testing board 300 so long as the one or more support rails 306 may beconfigured to substantially align each of the one or more opticalreceivers 304 of the sensor board with a corresponding socket 302 of thetesting board 300 such that optical signals transmitted by an opticaltransmitter (e.g., an optical transmitter 502 in FIG. 5) may be receivedby the corresponding optical receiver 314 of the sensor board 304 whenthe testing unit 102 is in an operational configuration. Still further,the sensor board 304 may also be disposed substantially parallel withrespect to the testing board 300 via the support rails 306 and locatedsuch that the distance between the sensor board 304 and the socket 302of the testing board 300 is less than 9.33 mm.

In some embodiments, and as shown in FIG. 3, the testing board 300 mayinclude a female connector 310 configured to receive a correspondingmale connector 308 defined by the sensor board 304. The connectionbetween the female connector 310 and the corresponding male connector308 may facilitate securing and aligning the sensor board 304 withrespect to the testing board 300 such that optical communication betweenthe one or more optical receivers 314 and the plurality of opticaltransmitters 502 (e.g., shown in FIG. 5) received by the socket 302 aremaintained. As would be understood by one or ordinary skill in the artin light of the present disclosure, each of the testing board 300 or thesensor board 304 may define any attachment mechanism (e.g., snaps,grooves, or the like) in order to secure the sensor board 304 to thetesting board 300.

With reference to FIG. 4, a top view of the testing board 300 configuredto support eight (8) optical transmitters (not shown) via eight (8)sockets 302 is illustrated. In some embodiments, the testing board 300may be configured (e.g., sized and shaped) so as to form a connectingportion 400 and a testing portion 402. In such an embodiment, theconnecting portion 400, including the edge connector 106 described abovewith reference to FIGS. 1-2, may define a first width W₁, and thetesting portion 402 may define a second width W₂. As shown in FIG. 4,the first width W₁ of the connection portion 400 may be less than thesecond width W₂ of the testing portion 402 so as to form a t-shapedtesting board 300. While described with reference to a t-shaped testingboard 300 with eight (8) sockets 302, the present disclosurecontemplates that any number of sockets 302 may be supported by thetesting board 300 in any configuration. Furthermore, the presentdisclosure contemplates that the testing board 300 may be any shape orsize so as to be received by a corresponding backplane element (e.g.,backplane element 104 in FIG. 1).

With reference to FIGS. 5-6A, a socket 302 configured to receive asubstrate 500 supporting a plurality of optical transmitters 502 (e.g.,VCSELs) is illustrated. As shown, the substrate 500 may be configured tobe received by a socket 302 such that electrical signals received by thesocket 302 (e.g., via electrical communication with the testing board300) may be transmitted from the socket 302 to the substrate 500, andfurther transmitted to a plurality of optical transmitters 502 supportedthereon. The plurality of optical transmitters 502 may be configured toconvert the electricals signals to corresponding optical signals fortransmission by the optical transmitters 502. As shown in FIG. 6A, theplurality of optical transmitters 502 may be connected with a contactpoint 602 of the substrate 500 via one or more wire bonds 600. Asdescribed hereinafter with regard to one or more testing methods appliedto the plurality of optical transmitters 502, the connection of at leastone optical transmitter 502 with a corresponding contact point 602 viathe wire bond 600 may allow various parameters or outputs (e.g., anoutput voltage, an output current, an operating temperature, etc.) to betransmitted as electrical signals from the respective opticaltransmitter 502 to a control unit (e.g., the control unit 112 in FIG. 1)for analysis. In some embodiments, the substrate 500 received by thesocket 302 may support sixteen (16) optical transmitters (e.g., VCSELs).While described in reference to sixteen (16) optical transmitters 502supported by a single substrate 500, the present disclosure contemplatesthat any number of optical transmitters 502 may be supported by acorresponding substrate 500 in any configuration. Furthermore, withreference to FIG. 6-6A, the present disclosure contemplates that anyorientation or configuration of wire bonds 600 and contact points 602may be unitized by embodiments of the present invention such that one ormore of the plurality of optical transmitters 502 is in electricalcommunication with a driver (e.g., driver 108).

With reference to FIG. 7, a bottom view of the sensor board 304 isillustrated. As shown, the bottom surface of the sensor board 304 may beconfigured to support one or more optical receivers 314 (e.g.,photodiodes). When in an operational configuration, in which the bottomsurface of the sensor board is substantially aligned with the testingboard 300, each optical receiver 314 may be configured to receiveoptical signals transmitted by the plurality of optical transmitters 502and configured to convert the optical signals to correspondingelectrical signals. In some embodiments, the sensor board 304 maysupport eight (8) optical receivers 314. However, the present disclosurecontemplates that any number of optical receivers 314 may be supportedby the sensor board 304 so as to receive optical signals provided by thecorresponding sockets 302 (via the plurality of optical transmitters502) of the testing board 300. As would be evident to one of ordinaryskill in the art in light of the present disclosure, the sensor board304, in some embodiments, may support the same number of opticalreceivers 314 as the number of sockets 302 supported by thecorresponding testing board 300. Furthermore the configuration ororientation of these optical receivers 314 may match that of theorientation of sockets 302 of the testing board 300 so as allow foroptical communication between the optoelectronic elements supportedthereon. In an example embodiment described herein, the sensor board 304may define eight (8) optical receivers 314 positioned to substantiallyalign with eight (8) corresponding sockets 302 of the testing board 300such that the set of sixteen (16) optical transmitters 502 of eachsocket 302 is in optical communication with a single correspondingoptical receiver 314. Accordingly, in such an embodiment, the sensorboard 304 supports eight (8) optical receivers 314 in opticalcommunication with a maximum of one hundred twenty-eight (128) opticaltransmitters 502.

As described below in detail with reference to particular testingmethods, the testing system 100 may serve to provide electrical inputsto a plurality of optical transmitters 502 and monitor correspondingoutput parameters. By way of example, with reference to FIGS. 1, 3, and5, the control unit 112 may execute a testing method by directing thedriver 108 to provide a current input to at least one of the pluralityof optical transmitters 502. The control unit 112 may provide thiscommand via electrical signals transmitted to the driver 108. The driver108 may then provide a corresponding current input to the testing unit102 via electrical signals transmitted by the driver 108 to the testingunit via the rigid-flex PCB 110, the backplane 104, and the edgeconnector 106 (FIG. 1). The electrical signals may then be provided toat least one optical transmitter 502 via electrical traces of thetesting board 300, socket 302, and substrate 500. The opticaltransmitter 502 may convert the electrical signals to optical signalsand may transmit the optical signals to the corresponding opticalreceiver 314 of the sensor board 304. The optical receiver 314 may thenconvert the optical signals to corresponding electrical signals. Theseelectrical signals may be provided to the control unit 112 via thedriver 108 and backplane 104 through the connection provided byconnectors 308, 310. The control unit 112 may analysis and/or determinevarious parameters or outputs of the optical transmitter 502 based uponthese electrical signals to determine passage or failure of the opticaltransmitter. Although described as providing a current input to a singleoptical transmitter, the present disclosure contemplates that thecontrol unit 112 and/or driver 108 may selectively apply inputs to anynumber or combination of the plurality of optical transmitters 502.

Optical Transmitter Testing Methods

The apparatus 200, method, and computer program product of an exampleembodiment will now be described in conjunction with the operationsillustrated in FIGS. 8-12.

With reference to FIG. 8, a flow chart is provided that illustrates anoptical transmitter testing method 800 for use with some embodimentsdescribed herein. The method 800 may include performing a continuitytesting method, an LIV testing method, an IV testing method, and astress testing method on an optical transmitter 502. The apparatus 200(e.g., the control unit 112 and/or driver 108) may include means, suchas the processor 202 of FIG. 2 or the like, for performing a continuitytesting method at Block 802. The continuity testing method (e.g., method900 in FIG. 9) may be used to determine if the elements of the systemfor testing optical transmitters 100 are correctly installed, such thatthe testing methods can be carried out to provide valid results. Theapparatus 200 may further include means, such as the processor 202 orthe like, for performing an LIV testing method at Block 804. The LIVtesting method (e.g., method 1000 in FIG. 10) may be used to determinethe periodic characterization of the IV curve (e.g., current (I) versusvoltage (V)) of at least one optical transmitter of the plurality ofoptical transmitters (e.g., the optical transmitters 502 in FIG. 5)along with a periodic characterization of the optical power of eachrespective optical transmitter. The apparatus 200 (e.g., the controlunit 112 and/or driver 108) may again include means, such as theprocessor 202 or the like, for performing a continuity testing method atBlock 806. The apparatus 200 may further include means, such as theprocessor 202 or the like, for performing an IV testing method at Block808. The IV testing method (e.g., method 1100 in FIG. 11) may be used todetermine the periodic characterization of the IV curve (e.g., current(I) versus voltage (V)) of at least one optical transmitter of theplurality of optical transmitters 502 over a testing time. The apparatus200 may also include means, such as the processor 202 or the like, forperforming a stress testing method at Block 810. The stress testingmethod (e.g., method 1200 in FIG. 12) may be used to predict the failureof at least one optical transmitter of the plurality of opticaltransmitters 502 by applying an increasing current input for an extendedtesting period. As shown, the method 800 may be repeated for any numberof iterations over any length of testing time to meet applicableindustry standards.

With reference to FIG. 9, a flowchart is provided that illustrates thecontinuity testing method 900 for use with some embodiments describedherein. The apparatus 200 (e.g., the control unit 112 and/or driver 108in FIG. 1) may include means, such as the processor 202 or the like, forapplying a first constant current input to an optical transmitter 502 ofa plurality of optical transmitters at Block 902. As described above,the control unit 112 and/or driver 108 may be configured to provide acurrent input to at least one optical transmitter 502 of a plurality ofoptical transmitters. In some embodiments, the current input at Block902 may be selectively applied to particular optical transmitters 502defined by a user or defined as a parameter of the continuity testingmethod 900.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may include means, such as the processor 202 or the like, formonitoring a first output voltage of the optical transmitter 502 atBlock 904 and means for monitoring a first operating temperature of thecorresponding substrate 500 supporting the optical transmitter 502 atBlock 906. As described above, the control unit 112 may be incommunication with one or more sensors configured to monitor variousoutputs of the optoelectronic elements of the system 100. At Block 904,the control unit 112 may be in electrical communication with a currentsensor or transducer configured to monitor a current outputted by theoptical transmitter 502 as a result of the current input by the driver108. In other embodiments, the driver 108 and/or control unit 112 maycalculate or otherwise determine the output voltage of the opticaltransmitter via application of Ohm's law. In particular, Ohm's lawstates that V=I·R, where V is voltage, I is current, and R is resistance(a characteristic of the optical transmitter 502). By utilizing anoptical transmitter 502 with a particular resistance value and applyinga constant current at Block 902, a change in the voltage of the opticaltransmitter 502 may be monitored using Ohm's law. Similarly, at Block906, the control unit 112 may be in electrical communication with athermometer or other temperature sensor configured to monitor anoperating temperature of the substrate 500 supporting the opticaltransmitter 502.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may also include means, such as the processor 202 or the like,for determining a first voltage pass state or a first voltage fail stateof the optical transmitter 502 based on a comparison of the first outputvoltage to a first output voltage threshold at Block 908. The firstoutput voltage monitored by the control unit 112 at Block 904 may becompared to a first output voltage threshold at Block 908. In someembodiments, the first output voltage threshold may be a user-definedacceptable range of output voltage values, such that a first voltagepass state is determined in an instance in which the first outputvoltage satisfies the first output voltage threshold. Conversely, afirst voltage fail state may be determined in an instance in which thefirst output voltage does not satisfy the first output voltagethreshold. In some other embodiments, the first output voltage thresholdmay be determined with reference to an industry standard for opticaltransmitters 502.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may include means, such as the processor 202 or the like, fordetermining a first temperature pass state or a first temperature failstate of the optical transmitter 502 based on a comparison of the firstoperating temperature to a first operating temperature threshold atBlock 910. The first operating temperature monitored by the control unit112 at Block 906 may be compared to a first operating temperaturethreshold at Block 910. In some embodiments, the first operatingtemperature threshold may be a user-defined acceptable range ofoperating temperature values, such that the first temperature pass stateis determined in an instance in which the first operating temperaturesatisfies the first operating temperature threshold. Conversely, a firstoperating temperature fail state may be determined in an instance inwhich the first operating temperature does not satisfy the firstoperating temperature threshold. In some other embodiments, the firstoperating temperature threshold may be determined with reference to anindustry standard for substrates 500.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may include means, such as the processor 202 or the like, fordetermining a first pass state at Block 912 in an instance in which thefirst voltage pass state and the first temperature pass state aredetermined. By way of example, if the control unit 112 determines thatthe first output voltage of the optical transmitter 502 and the firstoperating temperature of the substrate 500 satisfy their respectivethresholds, the apparatus 200 may determine a first pass state of theoptical transmitter 502. In some embodiments, the control unit 112 mayperform the continuity testing method 900 for each optical transmitter502 of the testing unit 102 sequentially (e.g., one at a time). In otherembodiments, the continuity testing method 900 may be performed on anynumber of optical transmitters simultaneously. In some furtherembodiments, the apparatus 200 may further include means, such as theprocessor 202 or the like for, maintaining a constant ambienttemperature of the plurality of optical transmitters while performingthe continuity testing method 900.

With reference to FIG. 10, a flowchart is provided that illustrates anLIV testing method 1000 for use with some embodiments described herein.In monitoring and determining the reliability of optical components(e.g., optical transmitters 502), the LIV testing method 1000 may beused to monitor not only the optical parameters (e.g., monitored via anIV testing method 1100), but also the electrical parameters (e.g.,current) of the optical components. As above with reference to method900, the apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) in method 1000 may include means, such as the processor 202 orthe like, for applying a second constant current input to the opticaltransmitter 502 of the plurality of optical transmitters at Block 1002.Further, the apparatus 200 may also include means, such as the processor202 or the like, for monitoring a second output voltage of the opticaltransmitter at Block 1004 and for monitoring a second operatingtemperature of the corresponding substrate supporting the opticaltransmitter at Block 1008. The control unit 112 may again be inelectrical communication with various sensors in order to monitor thesecond output voltage and the second operating temperature at Blocks1004, 1008.

Additionally, the apparatus 200 (e.g., the control unit 112 and/ordriver 108 in FIG. 1) in method 1000 may include means, such as theprocessor 202 or the like, for monitoring a first sensor voltage of acorresponding optical receiver in optical communication with the opticaltransmitter at Block 1006. As described above with reference to FIG. 7,the system 100 may define one or more optical receivers 314 in opticalcommunication with one or more optical transmitters 502. As such, thecontrol unit 112, at Block 1006, may similarly monitor the voltage ofthe corresponding optical receiver 314 receiving optical signals fromthe at least one optical transmitter 502. This first sensor voltageoutput by the optical receiver 314 may be representative of the opticalpower of the optical transmitter 502.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may include means, such as the processor 202 or the like, foriteratively applying a modified second current input to the opticaltransmitter at Block 1010. As described above at Block 1002, the controlunit 112 and/or driver 108 may modify the current input (e.g., increasethe current input) in order to affect the outputs of the opticaltransmitters 502, the optical receiver 314, and/or the substrate 500.Following this application of the modified second current input to theoptical transmitter 502 at Block 1010, the apparatus 200 may includemeans, such as the processor 202 or the like, for monitoring at leastone third output voltage of the optical transmitter at Block 1012,monitoring at least one second sensor voltage of the correspondingoptical receiver at Block 1014, and monitoring at least one thirdoperating temperature of the corresponding substrate at Block 1016. Insuch a method 1000, the control unit 112 may collect or otherwise storethese iterative outputs in order to predict the failure or reliabilityof the optical transmitter 512. Said another way, the control unit 112may collect data corresponding to the output voltage of the opticaltransmitter, the sensor voltage of the optical receiver, and theoperating temperature of the substrate from each iteration of themodified second current input. The control unit 112 may use this data tocalculate various testing parameters described hereinafter.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may further include means, such as the processor 202 or thelike, for calculating one or more first output parameters of the opticaltransmitter based on the second output voltage, the third outputvoltage, the second operating temperature, and the third operatingtemperature at Block 1018. In some embodiments, the first testing outputparameters include at least one of a leakage current, an opticaltransmitter resistance, an optical threshold voltage, a resistancedeviation, or a threshold voltage deviation. In some embodiments,additional system parameters may also be monitored by the method 1000 atvarious locations in the system 100. By way of example, an outputcurrent of a current source and/or optical transmitter (e.g., opticaltransmitter 502) may also be monitored at the current source and/oroptical transmitter, respectively. Additionally, the apparatus 200(e.g., the control unit 112 and/or driver 108 in FIG. 1) may includemeans, such as the processor 202 or the like, for calculating a firstoptical power drift parameter based on the first sensor voltage outputand the second sensor voltage output at Block 1020.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may also include means, such as the processor 202 or the likefor determining a first testing parameter pass state or a first testingparameter fail state of the optical transmitter 502 based on acomparison of the one or more first testing output parameters to acorresponding first testing parameter threshold at Block 1022. The firstoutput parameters calculated by the control unit 112 at Block 1018 maybe compared to one or more first testing parameter thresholds. In someembodiments, the first testing parameter thresholds may be user-definedacceptable ranges of first testing output parameters such that a firsttesting parameter pass state is determined in an instance in which thefirst testing output parameters satisfy the one or more first testingparameter thresholds. Conversely, a first testing parameter fail statemay be determined in an instance in which the first testing outputparameters do not satisfy the first testing parameter threshold.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may include means, such as the processor 202 or the like, fordetermining a first power drift pass state or a first power drift failstate of the optical transmitter 502 based on a comparison of the firstoptical power drift parameter to a first optical power drift thresholdat Block 1024. The first optical power drift parameter calculated by thecontrol unit 112 at Block 1020 may be compared to a first optical powerdrift threshold. In some embodiments, the first optical power driftthreshold may be a user-defined acceptable range of optical power driftvalues such that the first optical power drift pass state is determinedin an instance in which the first optical power drift parametersatisfies the first optical power drift threshold. Conversely, a firstpower drift fail state may be determined in an instance in which thefirst optical power drift parameter does not satisfy the first opticalpower drift threshold. In some other embodiments, the first opticalpower drift threshold may be determined with reference to an industrystandard for optical transmitters 502.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may include means, such as the processor 202 or the like, fordetermining a second pass state in an instance in which the firsttesting parameter pass state and the first power drift pass state aredetermined at Block 1026. By way of example, if the control unit 112determines that the first testing output parameters and the firstoptical power drift parameter of the optical transmitter 502 satisfytheir respective thresholds, the apparatus 200 may determine a secondpass state of the optical transmitter 502. In some embodiments, thecontrol unit 112 may perform the LIV testing method 1000 for eachoptical transmitter 502 of the testing unit 102 sequentially (e.g., oneat a time). In other embodiments, the LIV testing method 1000 may beperformed on any number of optical transmitters simultaneously.

With reference to FIG. 11, a flowchart is provided that illustrates anIV testing method 1100 for use with some embodiments described herein.The IV testing method 1100 of FIG. 11 generally tracks the LIV testingmethod 1000 described above with reference to FIG. 10. However, the IVtesting method 1100 of FIG. 11 does not monitor a first sensor voltageof a corresponding optical receiver 314 in optical communication with anoptical transmitter 502 to subsequently determine an optical power driftparameter (e.g., at Block 1020 in FIG. 10), but instead provides for afirst testing time during which the second constant current input isapplied at Block 1102. For the sake of completeness, the apparatus 200(e.g., the control unit 112 and/or driver 108 in FIG. 1) in method 1100may include means, such as the processor 202 or the like, for applying asecond constant current input to an optical transmitter 502 of aplurality of optical transmitters at Block 1102; for monitoring a secondoutput voltage of the optical transmitter over the first testing time atBlock 1104; and for monitoring a second operating temperature of acorresponding substrate supporting the optical transmitter over thefirst testing time at 1106. The apparatus 200 (e.g., the control unit112 and/or driver 108 in FIG. 1) in method 1100 may also include means,such as the processor 202 or the like, for iteratively applying amodified second current input to the optical transmitter over the firsttesting time at 1108; for monitoring at least one third output voltageof the optical transmitter at Block 1110; and for monitoring at leastone third operating temperature of the corresponding substrate at Block1112. The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) in method 1100 may further include means, such as the processor202 or the like, for calculating one or more first testing outputparameters of the optical transmitter based on the second outputvoltage, the third output voltage, the second operating temperature, andthe third operating temperature at Block 1114; and for determining asecond pass state or a second fail state of the optical transmitterbased on a comparison of the one or more first testing output parametersto a corresponding first testing parameter threshold at Block 1116. Insome embodiments, the first testing time is about 45 minutes. In somefurther embodiments, the control unit 112 may also perform the IVtesting method 1100 for each optical transmitter 502 of the testing unit102 sequentially (e.g., one at a time). In other embodiments, the IVtesting method 1100 may be performed on any number of opticaltransmitters simultaneously.

With reference to FIG. 12, a flowchart is provided that illustrates astress testing method 1200 for use with some embodiments describedherein. The apparatus 200 (e.g., the control unit 112 and/or driver 108in FIG. 1) may include means, such as the processor 202 or the like, forapplying a third constant current input to an optical transmitter of aplurality of optical transmitters 502 for a second testing time at Block1202. As described above, the control unit 112 and/or driver 108 may beconfigured to provide a current input to at least one opticaltransmitter 502 of a plurality of optical transmitters. In someembodiments, the current input at Block 1202 may be selectively appliedto particular optical transmitters 502 defined by a user or defined as aparameter of the stress testing method 1200.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may include means, such as the processor 202 or the like, formonitoring a fourth output voltage of the optical transmitter over thesecond testing time at Block 1204 and for monitoring a fourth operatingtemperature of a corresponding substrate supporting the opticaltransmitter over the second testing time at Block 1206. As describedabove, the control unit 112 may be in communication with one or moresensors configured to monitor various outputs of the optoelectronicelements of the system 100. In some embodiments, the second testing timeis about 60 minutes. Additionally, in some alternative embodiments, anambient temperature of the plurality of optical transmitters 502 may bevariable over the second testing time.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may also include means, such as the processor 202 or the like,for analyzing if the fourth output voltage is above a maximum outputvoltage and if the fourth operating temperature above a maximumoperating temperature at Block 1208. In an instance in which the fourthoutput voltage is above a maximum output voltage or the fourth operatingtemperature is above the maximum operating temperature, the apparatusmay determine failure of the optical transmitter at Block 1210.

The apparatus 200 (e.g., the control unit 112 and/or driver 108 inFIG. 1) may also include means, such as the processor 202 or the like,for analyzing if a first change in the output voltage is above a voltagevariation threshold or if a first change in operating temperature isabove a temperature variation threshold at Block 1212, if these maximumvalues are not exceeded by the fourth output voltage or the fourthoperating temperature at Block 1208. In an instance in which the firstchange in the output voltage is above a voltage variation threshold orthe operating temperature variation is above the temperature variationthreshold, the apparatus 200 may determine failure of the opticaltransmitter at Block 1214. However, in an instance in which bothanalyses performed at Blocks 1208, 1212 are successful, the apparatus200 may determine passage of the optical transmitter at Block 1216. Insome embodiments, the control unit 112 may perform the stress testingmethod 1200 for each optical transmitter 502 of the testing unit 102sequentially (e.g., one at a time). In other embodiments, the stresstesting method 1200 may be performed on any number of opticaltransmitters simultaneously. Furthermore, the stress testing method 1200may also be repeated with increasing current inputs (e.g., thirdconstant current inputs at Block 1202) for an extended testing period(e.g., second testing time).

As described above, FIGS. 8-12 illustrate flowcharts of an apparatus200, method, and computer program product according to exampleembodiments. Each of the output values, output testing parameters, andthreshold values of the testing method described above may also relateto the reliability of optical transmitters. In particular, the testingmethods provided herein may be used to predict the failure of opticaltransmitters. Further, it will be understood that each block of theflowcharts, and combinations of blocks in the flowcharts, may beimplemented by various means, such as hardware, firmware, processor,circuitry, and/or other devices associated with execution of softwareincluding one or more computer program instructions. For example, one ormore of the procedures described above may be embodied by computerprogram instructions. In this regard, the computer program instructionswhich embody the procedures described above may be stored by a memory204 of an apparatus 200 employing an embodiment of the present inventionand executed by a processor 202 of the apparatus 200 (FIG. 2). As willbe appreciated, any such computer program instructions may be loadedonto a computer or other programmable device (e.g., hardware) to producea machine, such that the resulting computer or other programmable deviceimplements the functions specified in the flowchart blocks. Thesecomputer program instructions may also be stored in a computer-readablememory that may direct a computer or other programmable device tofunction in a particular manner, such that the instructions stored inthe computer-readable memory produce an article of manufacture theexecution of which implements the function specified in the flowchartblocks. The computer program instructions may also be loaded onto acomputer or other programmable device to cause a series of operations tobe performed on the computer or other programmable device to produce acomputer-implemented process such that the instructions which execute onthe computer or other programmable device provide operations forimplementing the functions specified in the flowchart blocks.

Accordingly, blocks of the flowcharts support combinations of means forperforming the specified functions and combinations of operations forperforming the specified functions for performing the specifiedfunctions. It will also be understood that one or more blocks of theflowcharts, and combinations of blocks in the flowcharts, may beimplemented by special purpose hardware-based computer systems whichperform the specified functions, or combinations of special purposehardware and computer instructions.

In some embodiments, certain ones of the operations above may bemodified or further amplified. Furthermore, in some embodiments,additional optional operations may be included. Modifications,additions, or amplifications to the operations above may be performed inother orders and/or combinations.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of teachings presented in theforegoing descriptions and the associated drawings. Although the figuresonly show certain components of the apparatus and systems describedherein, it is understood that various other components (e.g., componentsof printed circuit boards, transceivers, cables, etc.) may be used inconjunction with the cage receptacle assembly. Therefore, it is to beunderstood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.

What is claimed is:
 1. A system for testing optical transmitterscomprising: a testing unit comprising: a testing board supporting one ormore sockets via a top surface of the testing board, wherein each socketis configured to receive a substrate supporting a plurality of opticaltransmitters, wherein each optical transmitter is configured to convertelectrical signals to corresponding optical signals for transmission bythe optical transmitter; a sensor board supporting one or more opticalreceivers via a bottom surface of the sensor board, wherein each opticalreceiver is configured to receive the optical signals transmitted by theplurality of optical transmitters and configured to convert the opticalsignals to corresponding electrical signals; and one or more supportrails attached to one of the testing board or the sensor board andconfigured to engage the other of the testing board or the sensor board,and the one or more support rails are configured to substantially aligneach of the one or more optical receivers of the sensor board with acorresponding socket of the testing board such that the plurality ofoptical transmitters is in optical communication with the one or moreoptical receivers in an operational mode of the testing unit; and adriver in electrical communication with the plurality of opticaltransmitters of the one or more sockets and in electrical communicationwith the one or more optical receivers of the sensor board, wherein thedriver is configured to apply a current input to at least one of theplurality of optical transmitters and configured to monitor acorresponding output parameter.
 2. The system according to claim 1,wherein the driver is further configured to determine a pass state or afail state of the plurality of optical transmitters based on acomparison of the output parameter to an output parameter threshold. 3.The system according to claim 1, further comprising a backplane elementsupporting one or more testing units, wherein the backplane element isin electrical communication with the one or more testing units.
 4. Thesystem according to claim 3, wherein the backplane element supports fourtesting units.
 5. The system according to claim 3, wherein the driver iselectrically connected to the backplane element via a rigid-flex printedcircuit board.
 6. The system according to claim 3, further comprisingfour drivers, wherein each driver is configured to provide a current toone of the testing units supported by the backplane element.
 7. Thesystem according to claim 1, further comprising a control unit inelectrical communication with the driver and configured to execute atesting method with respect to the plurality of optical transmitters ofthe testing unit.
 8. The system according to claim 1, wherein eachtesting board supports eight sockets.
 9. The system according to claim1, wherein each socket is configured to receive a substrate supportingsixteen optical transmitters.
 10. The system according to claim 1,wherein the plurality of optical transmitters comprise vertical-cavitysurface-emitting lasers.
 11. The system according to claim 1, whereinthe one or more optical receivers comprise photodiodes.
 12. The systemaccording to claim 1, wherein the distance between the socket and thesensor board is less than 9.33 mm.
 13. The system according to claim 1,wherein the sensor board further comprises a male connector configuredto be received by a corresponding female connector defined by thetesting board.
 14. The system according to claim 1, wherein the testingunit defines a connecting portion having a first width and comprising anedge connector and defines a testing portion having a second width,wherein the second width is larger than the first width.
 15. The systemaccording to claim 14, wherein the edge connector is configured to bereceived by a corresponding connector of a backplane element.
 16. Thesystem according to claim 15, wherein the driver is in electricalcommunication with the backplane element via a rigid-flex printedcircuit board, and the backplane element is in electrical communicationwith the testing unit via the edge connector such that the current inputapplied by the driver is received by the plurality of opticaltransmitters via the backplane element.
 17. A method of manufacturing asystem for testing optical transmitters, the method comprising:providing a testing unit comprising: a testing board supporting one ormore sockets via a top surface of the testing board, wherein each socketis configured to receive a substrate supporting a plurality of opticaltransmitters, wherein each optical transmitter is configured to convertelectrical signals to corresponding optical signals for transmission bythe optical transmitter; a sensor board supporting one or more opticalreceivers via a bottom surface of the sensor board, wherein each opticalreceiver is configured to receive the optical signals transmitted by theplurality of optical transmitters and configured to convert the opticalsignals to corresponding electrical signals; and one or more supportrails attached to one of the testing board or the sensor board andconfigured to engage the other of the testing board or the sensor board,and the one or more support rails are configured to substantially aligneach of the one or more optical receivers of the sensor board with acorresponding socket of the testing board such that the plurality ofoptical transmitters is in optical communication with the one or moreoptical receivers in an operational mode of the testing unit; andproviding a driver in electrical communication with the plurality ofoptical transmitters of the one or more sockets and in electricalcommunication with the one or more optical receivers of the sensorboard, wherein the driver is configured to apply a current input to atleast one of the plurality of optical transmitters and configured tomonitor a corresponding output parameter.
 18. The method ofmanufacturing according to claim 17, further comprising providing abackplane element configured to support one or more testing units. 19.The method of manufacturing according to claim 18, further comprisingproviding one or more drivers, wherein each driver is configured toprovide a current to one of the testing units supported by the backplaneelement.
 20. The method of manufacturing according to claim 17, furthercomprising providing a control unit in electrical communication with thedriver and configured to execute a testing method with respect to theplurality of optical transmitters of the testing unit.